How does carbohydrate supply limit flower development in grape and kiwifruit vines? Annette Claire Richardson July 2014 Submitted in total fulfilment of the requirements of the degree of Doctor of Philosophy School of Agricultural and Wine Sciences Charles Sturt University Wagga Wagga Australia i Table of Contents Table of Contents ii List of Figures vii List of Tables xix Certificate of Authorship xxvi Acknowledgements xxviii Abstract xxx Abbreviations xxxii 1 Literature review 1 1.1 Introduction 1 1.2 The flowering process 3 1.2.1 Floral Initiation 3 1.2.2 Floral organ morphogenesis 7 1.3 How does flowering behaviour of perennials affect crop yield? 11 1.3.1 Are yields of perennial fruiting crops similar? 11 1.4 Is low flower production typical of fruiting vines? 16 1.4.1 Are the flowering behaviours of grape and kiwifruit vines similar? 16 1.4.2 When do carbohydrates limit flower development of grape and kiwifruit? 24 1.5 Thesis aims and hypotheses 28 2 General materials and methods 31 2.1 Plant material 31 2.1.1 Commercial vines 31 2.1.2 Potted vines 35 2.2 Meteorological data 38 2.3 Vine phenology 38 2.3.1 Budbreak and flowering 38 2.3.2 Phenological stages of development 39 2.4 Leaf area estimation 42 2.5 Gas exchange 42 ii 2.6 Carbohydrate analysis 43 2.6.1 Tissue extraction 43 2.6.2 Starch determination 43 2.6.3 Soluble carbohydrate determination 44 2.7 Data handling and statistical analysis 44 2.7.1 Data handling 44 2.7.2 Data analysis 45 2.7.3 Data plots and curve fitting 45 3 Seasonal patterns of kiwifruit and grapevine development 47 3.1 Introduction 47 3.2 Materials and Methods 50 3.2.1 Plant Material 50 3.2.2 Vine phenology 50 3.2.3 Gas exchange measurements 52 3.2.4 Net carbon balance 53 3.2.5 Sampling and carbohydrate analysis 53 3.2.6 Statistical analysis 55 3.3 Results 56 3.3.1 Vine phenology 56 3.3.2 Gas exchange 67 3.3.3 Total carbohydrate concentrations 77 3.4 Discussion 91 3.4.1 Seasonal patterns of vine growth 91 3.4.2 Carbohydrate composition 95 3.4.3 Gas exchange 98 3.4.4 Carbon acquisition and balance 100 3.4.5 Whole vine carbon budgets 102 3.4.6 Summary 103 4 Carbohydrate supply during inflorescence initiation and bud development 105 4.1 Introduction 105 iii 4.2 Materials and Methods 107 4.2.1 Plant Material 107 4.2.2 Experimental design 107 4.4 Results 114 4.4.1 Shoot growth 114 4.4.2 Axillary bud and internode dry weight in winter 120 4.4.3 Winter bud and internode carbohydrate content 124 4.4.4 Effects on spring development 127 4.4.5 Relationship between carbohydrate content, dry weight and bud performance 136 4.5 Discussion 138 4.5.1 Effects of shoot treatments on inflorescence initiation 139 4.5.2 Seasonal effects on shoot growth and floral development 141 4.5.3 Effects of treatments on shoot development and inflorescence production 143 4.5.4 Summary 144 5 Modifying carbohydrate supply during autumn: effect on the early stages of floral morphogenesis in grape and kiwifruit vines 147 5.1 Introduction 147 5.2 Materials and Methods 150 5.2.1 Plant material 150 5.2.2 Experimental design 150 5.2.3 Measurements 152 5.3 Results 155 5.3.1 Total carbohydrate concentrations and content 155 5.3.2 Amount of budbreak and flowering 163 5.3.3 Time of budbreak and flowering 171 5.3.4 Shoot growth 180 5.4 Discussion 182 5.4.1 Effect of treatments on total carbohydrate accumulation 182 5.4.2 Effects of autumn shade and girdling on subsequent flower production 185 iv 5.4.3 Effect of girdling on other metabolites 187 5.4.4 Summary 188 6 Carbohydrate supply during floral sex organ development 190 6.1 Introduction 190 6.2 Materials and Methods 192 6.2.1 Plant material 192 6.2.2 Experimental design and treatments 192 6.2.3 Measurements 195 6.2.4 Statistical analysis 197 6.3 Results 198 6.3.1 Shoot measurements 198 6.3.2 Inflorescence and flower measurements 203 6.3.3 Fruit set, seed number and seed weight 206 6.3.4 Yield 211 6.3.5 Shoot dry weight and leaf area 218 6.3.6 Shoot total carbohydrate concentrations and content 228 6.3.7 Gas exchange 233 6.3.8 Net carbon balance 241 6.4 Discussion 246 6.4.1 Floral morphogenesis 247 6.4.2 Shoot development prior to anthesis 248 6.4.3 Shoot development after anthesis 252 6.4.4 Pollination and fruit set 254 6.4.5 Changes in carbon supply before anthesis influences final yield 255 6.4.6 Summary 256 7 Conclusions and Integration 259 7.1 Hypothesis 1: 259 7.2 Hypothesis 2: 263 7.3 Hypothesis 3: 264 7.4 Hypothesis 4: 266 7.5 Future studies 269 v 7.6 Overall Summary 270 References 273 Appendix 1 Kiwifruit and grape pest and disease programme 293 Appendix 2 Meteorological Data 295 Appendix 3 Leaf area determination 300 Appendix 4 Measurements of SolarshadeTM characteristics 302 vi List of Figures Figure 1.1: Key stages of floral development in grape buds. Reproduced from Dunn and Martin (2007). ....................................................................... 19 Figure 1.2. Key stages in the floral development of kiwifruit buds as described by Brundell (1975c) and Walton et al. (1997). .............................. 21 Figure 2.1: ‘Hayward’ vines on ‘Bruno’ rootstocks were 24-years-old, cane- pruned and grown on a pergola at the Kerikeri Research Centre. ................ 34 Figure 2.2: ‘Shiraz’ vines on ‘101-14-m470’ rootstocks were five-years-old, cane-pruned and grown on a Smart-Dyson split canopy trellis at Marsden Estate. .......................................................................................................... 34 Figure 2.3: ‘Cabernet Sauvignon’ vines on ‘SO4’ rootstocks were 20-years- old, cane pruned and trained on a VSP system at Ivana Wines Vineyard. ... 35 Figure 2.4: ‘Hayward’ and ‘Cabernet Sauvignon’ vines were grown in pots at the Kerikeri Research Centre for use in multi-season studies. ..................... 36 Figure 3.1: Timing of key growth stages for ‘Hayward’ (A, B and C), ‘Shiraz’ (D, E and F) and ‘Cabernet Sauvignon’ (G) vines. Data are for the 2008/2009 season (A and D), 2009/2010 season (B and E) and the 2010/2011 season (C, F and G). .................................................................. 59 Figure 3.2: Dynamics of budbreak in A, 2009/2010 and B, 2010/2011 for ‘Hayward’ (), ‘Shiraz’ () and ‘Cabernet Sauvignon’ (; 2010/2011 only) vines. Data are the means ± SEM, n = 16. The lines are the fit of data to the Boltzmann sigmoid function. ......................................................................... 61 Figure 3.3: Dynamics of flowering in A, 2009/2010 and B, 2010/2011 seasons for ‘Hayward’ (), ‘Shiraz’ () and ‘Cabernet Sauvignon’ ( 2010/2011 only) vines. Data points are the means ± SEM, n = 16. The lines are the fit of data to the Boltzmann sigmoid function. ................................... 61 Figure 3.4: Periods of root loss (die back of root tips observed at sampling) and root growth (white root tips present at sampling). Data are for ‘Hayward’ vines (A, 2008/2009, B, 2009/2010 and C, 2010/2011) ‘Shiraz’ (D, 2008/2009, E, 2009/2010 and F, 2010/2011) and ‘Cabernet Sauvignon’ (G, 2010/2011). .................................................................................................. 63 Figure 3.5: The development of ‘Hayward’ (), ‘Shiraz’ () and ‘Cabernet Sauvignon’ () shoots across the 2010/2011 season. A, total leaf area per vii shoot, B, shoot length and C, shoot basal diameter. Data are means ± SEM, n = 16. ...........................................................................................................66 Figure 3.6: Changes in the total dry weight per shoot during the 2010/2011 season. Data for A, ‘Hayward’ (), leaves (), stems (), and fruit (), B, ‘Shiraz’ (), leaves (), stems (), and fruit () and C, ‘Cabernet Sauvignon’ (), leaves (), stems (), and fruit () shoots. Note the different scales for each vine cultivar. Data are means ± SEM, n = 6. .........67 Figure 3.7: Photosynthetic light responses of youngest mature leaves from A, ‘Hayward’ (), B, ‘Shiraz’ () and C, ‘Cabernet Sauvignon’ () shoots at anthesis (December 2010). Data are mean values ± SEM, n = 4. ...............68 Figure 3.8: Rates of A, photosynthesis, B, stomatal conductance, and C, transpiration measured concurrently under ambient conditions (temperature o -2 -1 21 - 33 C, PFD 329 - 1665 µmol (photons) m s , CO2 399.3 - 400.4 µmol -1 CO2 mol , VPD 1.02 - 2.64 kPa) over the growing season. Data for ‘Hayward’ (), ‘Shiraz’ () and ‘Cabernet Sauvignon’ () shoots are mean values for every second leaf on a shoot ± SEM, n = 8. .................................71 Figure 3.9: Changes in gas exchange with leaf position along a shoot from the base to the tip at around 80 DAB. Rates of A, photosynthesis, B, stomatal conductance and C, transpiration. Measurements were made concurrently under ambient conditions (temperature 28.2 - 33.1oC, PFD 677 - -2 -1 -1 1091 µmol (photons) m s , CO2 399 - 400 µmol CO2 mol , VPD 201 - 264 kPa) at approximately 80 DAB, during the very early stages of fruit development. Data are for ‘Hayward’ (), ‘Shiraz’ () and ‘Cabernet Sauvignon’ () shoots. Data are means ± SEM, n = 8. ...............................72 Figure 3.10: Changes in rates of carbon acquisition (A - C), carbon accumulated as biomass (D - F) and the net carbon balance of shoots (G - I) of ‘Hayward’ ( A, D, G), ‘Shiraz’ ( B, E, H) and ‘Cabernet Sauvignon’ ( C, F, I) shoots. Note the different scales between ‘Hayward’ and other vines for each parameter. Data are means ± SEM, n = 6. ....................................76 Figure 3.11: Changes in TNC in the leaves (A - C), developing axillary buds (D - F) and internodes G - I) of shoots during the 2008/09 (A, D, G), 2009/10 (B, E, H) and 2010/11 (C, F, I) growing seasons.